To play a game of tennis normally requires good weather and a dry suitable surface for a tennis court. The same conditions are also required if a player wants to exercise and practice his/her strokes or practice eye, hand and ball coordination skills. The player will also normally need to find a suitable partner to play against in order to test his/her skills. Many players do not own their own tennis courts and therefore have to book in advance the use of a court. Many tennis players have found it useful to hit a ball against a hard wall for practice purposes. The problem here is that a suitable wall or building is not always readily available or accessible. If the ball goes astray there is also the chance of the loss of the ball or the risk of property damage or personal injury...